1. Field of the Invention
Embodiments of the invention relate to the field of communication, and more specifically, to Orthogonal Frequency Division Multiple Access (OFDMA) or Orthogonal Frequency Division Multiplexing (OFDM) communication systems.
2. Description of Related Art
OFDM/OFDMA systems are becoming popular as a key technology for the next generation of wired and wireless or mobile communications. The Institute of Electrical and Electronics Engineers (IEEE) has provided several standards supporting air interface for fixed and mobile broadband wireless access (BWA) systems using OFDM/OFDMA such as the IEEE 802.16e for mobile BWA systems
One of the challenges facing OFDM/OFDMA systems design is estimating the channel responses in the receiver. Existing techniques to provide channel estimation has a number of drawbacks. One technique selects components less than the maximum guard band or the effective maximum length for all components in the time domain. The technique may not be reliable because the selected components may not be effective channel impulse response (CIR) components. In addition, there may be spectral leakage and signal distortions. Another technique uses minimum mean square error (MMSE) to find an optimum solution. This technique is complex, requiring time-consuming computations and may require a priori information such as signal-to-noise ration (SNR) or channel information to find the optimum MMSE solutions.